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Bug 463946

Summary: app-arch/tar: dynamically select compressors at runtime
Product: Gentoo Linux Reporter: Reuben Farrelly <reuben-gentoo-bugzilla>
Component: New packagesAssignee: Gentoo's Team for Core System packages <base-system>
Status: RESOLVED WONTFIX    
Severity: enhancement    
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
Whiteboard:
Package list:
Runtime testing required: ---

Description Reuben Farrelly 2013-03-31 00:15:33 UTC
I'm looking to use lbzip2 instead of standard bzip2, in order to gain the advantages of multiple CPU cores being used for compression.  Standard bzip2 only uses one core even on a multicore machine which means we don't take advantage of the CPU power anything even remotely modern.

lbzip2 is otherwise a drop in replacement for bzip2, that does support multi core compression.

However to do this we need to pass the --with-bzip2= flag to ./configure:

http://www.gnu.org/software/tar/manual/html_node/lbzip2.html

This RFE is to have lbzip2 and pbzip2 USE flag support added to the tar ebuild so that tar will be able to find and use these compression applications as well.
Comment 1 SpanKY gentoo-dev 2013-04-01 05:16:43 UTC
we're not going to add USE flags just to set --with-bzip2/etc... to different values at runtime.  you can use per-package env to set EXTRA_ECONF on your own system.

what might make sense is to have a wrapper and tell tar to run that, and the wrapper will select on the fly from a suite of possible tools.

but neither of these options are preventing you from doing:
  lbzip2 -dc foo.tar.bz2 | tar xf -
or:
  tar -I lbzip2 -xf foo.tar.bz2
Comment 2 Sam James archtester Gentoo Infrastructure gentoo-dev Security 2023-01-31 15:53:54 UTC
Use EXTRA_ECONF for tar or use app-alternatives.